Abstract: A handheld setting tool for driving a nail or bolt into a substrate, comprising: a drive, preferably a gas spring drive or an electrodynamic drive, which drives an actuator, which actuator is used to drive the nail or bolt into the substrate; characterised by: a decoupling device which at least partially decouples a first movement process of a first moving part or piston in the actuator, driven by the drive, from a second movement process of a second moving part or piston in the actuator so as to drive the nail or bolt into the substrate.

Abstract: A rational technique which can realize vibration suppression and reduction of unstable driving elements of a striker. A representative power tool, a first compensation mechanism moves a swinging mechanism from a swinging mechanism reference position to a swinging mechanism moving position and moves a cylinder to a second side, thereby increasing the volume of an air chamber. Further, the second compensation mechanism moves an intermediate element from an intermediate reference position to an intermediate element moving position and moves a striking element to the second side, thereby compensating the volume of the air chamber.

Abstract: A hand-held power tool is disclosed. The tool has a tool receptacle for holding a chiseling tool. A pneumatic percussion mechanism of the hand-held power tool includes a striker, an exciter and a guide tube. The striker is designed to apply impacts in the impact direction to the tool. The exciter is motor-driven. The striker is coupled by an air spring to the reciprocating movement of the exciter. The striker abutting the guide tube is guided along a working axis. During a movement between an impact position and the exciter, the striker is guided with a constant guide length on the guide tube and if the impact position is exceeded in the impact direction, the guide length is reduced. The hand-held power tool is equipped with an inclined guide, which inclines the striker relative to the working axis when the impact position is exceeded.

Abstract: This disclosure pertains to a post driver apparatus of simplified and compact construction. The apparatus can be easily attached to a vehicle equipped with a universal quick attach hitch and having auxiliary hydraulics, for example a farm or construction vehicle. The apparatus includes a hydraulic motor that is driven by the auxiliary hydraulics of the vehicle to which the apparatus is attached. The hydraulic motor rotates a drive wheel of the apparatus which is operatively connected with a weight piston of the apparatus. Rotation of the drive wheel lifts and then drops the weight piston on each rotation of the drive wheel. With the apparatus positioned on the top end of a post, each time the weight piston is dropped it impacts the top of the post and drives the post downwardly. The apparatus is equipped with a safety feature that prevents rotation of the drive wheel from operatively raising the weight piston until the apparatus is positioned on top of a post and exerts a force on the top end of the post.

Abstract: An impact driver or impact tool includes a motor, a motor housing that houses the motor, a grip housing integrally provided with the motor housing, a hammer case is disposed frontward of the motor housing, a spindle rotated by the motor, a hammer housed inside the hammer case and configured to be rotated by the spindle, and an anvil housed inside the hammer case which anvil is configured to be impacted by the hammer. In this impact driver, a length from a rear end of the motor housing to a front end of the anvil (i.e., the front-rear length of a main body) is less than 128 mm.

Abstract: The invention relates to a percussion tool having an internal combustion engine and a hammer mechanism that can be driven by the internal combustion engine by means of a transmission. A part of the engine housing, the transmission housing, or the impact hammer mechanism housing is enclosed by a cover. The cover is spaced at a distance from the remainder of the machine, so that a gap is present between the cover and the remainder of the machine. Cooling air can flow into the gap at the lower face of the cover and flow back out via a flue and an opening. The components beneath the cover are thereby effectively cooled, even without an additional cooling air blower.

Abstract: A pneumatic hammer mechanism is disclosed. The hammer mechanism features: a flying mass, which is movable along an impact axis; an impact surface, which limits a movement of the flying mass along the impact axis in the impact direction; an exciting piston, which limits a movement of the flying mass along the impact axis opposite from the impact direction; a pneumatic chamber between the flying mass and exciting piston; a drive for periodically moving the exciting piston with a stroke along the impact axis, wherein the flying mass is excited to a periodic movement between the impact surface and exciting piston. The stroke is selected as a function of a maximum length of the pneumatic chamber such that the periodic movement of the flying mass on the path between an impact on the impact surface and a minimum approach of the exciting piston intermittently has a velocity of zero.

Abstract: A tool body (1) has a coupler for engagement with any of a variety of tool heads such as a spade head (3), and a hatchet head (4). A tool comprising the body (1) and a tool head (3-10) is a hammer action tool. It may be used as a fork, spade, chisel, hatchet, or any tool which would benefit from a hammer action. A tubular shank (21) and a hammer (22) are together a hammer weight which is pushed down by the user until it hits a receiver (23), driving the tool head. A spring (24) returns the hammer (22) and a shank (21) back up to the start position ready for the next hammer action. It also acts to push the tool head out against a work surface for overhead work such as chiseling. A spring (25), acting between a hammer impact part (22) and the handle (21, 27) takes the shock out of the impact for the user's hands. The shank (21) and the hammer (22) slide up and down together on the box-section receiver tube (32).

Abstract: A nail gun with a rapidly attachable and detachable magazine assembly includes a nail gun, a magazine assembly and a quick joining mechanism. A handle portion of the nail gun has a quick joining pillar adapted to engage with the quick joining mechanism to attach the magazine assembly to the nail gun. By simply snap-fitting the quick joining pillar into a fixing element of the quick joining mechanism, the quick joining mechanism can naturally fix the quick joining pillar into the fixing element, and thus, the magazine assembly can be attached to the nail gun by simply a single action. Moreover, by pulling a pull rod of the quick joining mechanism and withdrawing the quick joining pillar from within the fixing element, the magazine assembly can be attached from the nail gun by also simply a single action.

Abstract: The invention is a striking mechanism for a handheld power tools in particular electric hammer. A piston is arranged in an axially bidirectionally movable manner in a guide tube. A striker is provided which acts on a striking pin and which is held in a movable manner in the guide tube. A compression space is delimited by the piston and the striker such that an air cushion is enclosed therein. It is proposed that at least one spring element is provided between the striker and the striking pin.

Abstract: A hand-held drive-in power tool for driving-in fastening elements includes a drive-in ram (13) displaceably arranged in a guide (12), a drive (30) for driving the drive-in ram (13) and having at least one driving spring member (31) for displacing the drive-in ram (13) and formed of a fiber-reinforced plastic material, and a device (70) for preloading the driving spring member (31).

Abstract: A percussive mechanism, which is provided in the form of an, e.g. pneumatic spring percussive mechanism, comprises an electrodynamic linear drive, a drive piston, which can be reciprocally moved inside a percussive mechanism housing by the linear drive, and a percussive piston. An additional hollow space is provided in front of and/or behind the drive piston and can be isolated at least in part from the surrounding area so that a pneumatic spring can be created in the additional hollow space. The pneumatic spring slows the drive piston at its returning points and facilitates a returning motion without loading the electrodynamic linear drive.

Abstract: The invention is a striking mechanism for a handheld power tools in particular electric hammer. A piston is arranged in an axially bidirectionally movable manner in a guide tube. A striker is provided which acts on a striking pin and which is held in a movable manner in the guide tube. A compression space is delimited by the piston and the striker such that an air cushion is enclosed therein. It is proposed that at least one spring element is provided between the striker and the striking pin.

Abstract: A nail gun includes a power coil for moving a plunger in two opposed directions. The plunger is first moved away from a nail, and force from this movement is stored in a force storage mechanism. The plunger is then driven by the coil in an opposed direction, and the force stored within the forced storage mechanism is released, such that the released force and the power force from the coil are combined to drive a nail into a work piece.

Abstract: A method of controlling a single-phase linear motor (1) for driving a striking mechanism (2) with a loose coupling (4) between a runner (5) of the linear motor (1) and a striker (6) of the striking mechanism (2) has, within a striking period in which exactly one force impact (K) of the striker (6) is carried out on a tool (8) or an anvil (7), a pull phase (Z) in which the loose coupling (4) contacts a runner-side contact surface (KL) with a one-sided constrained contact and a push phase (D) in which the loose coupling (4) contacts a striker-side contact surface (KS) with a one-sided constrained contact, and a change phase (W) provided between the pull phase (Z) and the push phase (D) in which the one-sided constrained contact changes between the two contact surfaces (KL-KS) along a contactless reciprocating gap (S) in that the runner (5) releases the one-sided constrained contact with one contact surface (KL/KS) in a regulated manner and produces the one-sided constrained contact with the other contact surfac

Abstract: An attachment for an impact hammer for translating the hammer's typical forwardly directed impact force into a rearwardly directed pulling force while still allowing the user to maintain a conventional orientation of the hammer relative to the work piece intended to be pulled. The attachment comprises a housing defining a cavity with a hammer bit axially movable therein and having an impacting head urged rearwardly by a bias structure which responds to a forward impact force by the impact hammer to cause the hammer bit head to exert impact force on the work piece in a rearward direction.

Abstract: A power tool (1) has a percussive driving implement for driving an impact tool (8). The driving implement, which may be hydraulic or pneumatic, retracts the impact tool (8) on its return stroke, against the force developed by heavy-duty elastic ropes (24). During the impact stroke the impact tool (8) is urged downwardly by the elastic ropes and, if the tool is upright, by gravity. At the start of the impact stroke the ram (10) is uncoupled by a ball clutch. At the beginning of the return stroke the ball clutch acts to couple the ram once again to the weight (20) and impact tool (8), in order to lift these to the retracted position. The uncoupling of the ram for the impact stroke reduces the loss arising from the resistance of the ram.

Abstract: The invention relates to a pneumatic percussive tool for a paving breaker and/or a hammer drill comprising a drive piston which is displaceable both backwards and forwards by a crankshaft and arranged in a percussion piston which is displaceable both backwards and forwards. A hollow chamber is connected to a compensating chamber by an idling air channel and embodied between the drive piston and the percussion piston in order to receive a pneumatic spring. A valve is arranged in the idling air channel, the opening and closing position thereof depending on the rotational speed of the crankshaft. If the rotational speed of the crankshaft falls below a predetermined value, the valve opens the connection between the hollow chamber and the compensating chamber so that a pneumatic spring can no longer be to embodied in the hollow chamber and the pneumatic percussion tool is placed in a idling position.

Abstract: A hand-guided vibration tamper, which is driven by a motor laterally cantilevered on the tamper head, is provided with guard plates covering its underside and lateral sides. The underside and lateral guard plates are connected to a housing for the motor, and the underside guard plate is fastened near its free end to the motor and/or an air circulation hood for the motor. Preferably, the underside guard plate is a thick-walled aluminum plate screwed together with the lateral guard plates and extends beyond to protect the air circulation hood with its extension. Advantageously, the motor is also protected by a substantially closed, upper covering connected to the lateral guard plates.

Abstract: A double action pneumatic spring percussion mechanism has an air supply mechanism. A percussion piston is movable with a driving piston. In an air-supply position, ambient air is supplied through an air inlet to a front pneumatic spring. When the percussion piston and driving piston are moved accordingly relative to each other, a loading hole is opened, through which air under increased pressure can flow out of the front pneumatic spring into a rear pneumatic spring, ensuring an increase of pressure in the rear pneumatic spring. The air pressure increase in both pneumatic springs makes it possible to use the pneumatic spring percussion mechanism even in conditions of operation with a low ambient air pressure.

Abstract: A device for breaking concrete and similar frangible materials to reduce it to rubble includes a power plunger and a trigger mechanism mounted within a casing. The casing may be carried on and operated by construction equipment such as a back hoe. The trigger mechanism is operative to release the plunger for allowing it to be fired by spring means or dropped by gravity for a preset distance against the concrete. The power plunger has a latch member affixed thereto and forming one element of the trigger mechanism. The element consists of a concave spherical latching edge portion on its underside. The trigger mechanism also includes a releasable trigger having a convex spherical latching edge portion which mates with the concave portion. The trigger initially catches beneath the latch member, and is then pivoted to release the latch member and allow the power plunger to be fired. The mating spherical latching surfaces provide for a smooth, minimal-wear release of the trigger mechanism.

Abstract: A device for breaking concrete and similar frangible materials to reduce it to rubble includes a power plunger and an actuator plunger mounted within a casing. The casing is carried on and operated by construction equipment such as a back hoe. As the back hoe is operated to cock the power plunger by moving the actuator plunger toward the concrete surface, a trigger mechanism affixed to the actuator plunger lifts the power plunger and an associated latch member to load a coil spring associated with the power plunger and presses against the latch member. As the coil is fully compressed, the trigger mechanism engages a trigger operating abutment and releases the latch member. The coil spring then fires the power plunger against the concrete.

Abstract: In a ram boring machine that has a striking piston reciprocating in a tubular housing and a striking tip that may be formed as a chisel and projects from the housing, connection of the striking tip to the housing by means of a bayonet joint makes installation and removal or replacement of the striking piston or a worn chisel possible in a simple manner.

Abstract: An upright guide bar is provided having upper and lower ends and the lower end include structure for releasable engagement with the upper end portion of an upstanding stake to be driver downwardly. A downwardly opening drive housing having upper and lower ends also is provided and the upper end of the guide bar is guidingly telescoped into the lower end of the housing. The lower housing end includes a downwardly facing abutment surface for downward abutting engagement with the stake upper end and the lower end of the housing includes an interior guide sleeve removably mounted therein through which the guide bar is slidingly received, the upper end of the guide bar and the guide sleeve having opposing abutment surface structures limiting upward movement of the housing relative to the guide bar.

Abstract: A portable hammer machine comprises a cylinder (11) in which a reciprocating drive piston (40) via a gas cushion in a working chamber (44) repeatedly drives a hammer piston (15) to impact on and to return from a tool (20) carried by the machine as soon as a feeding force is applied via the machine housing (10) to the tool (20) under compression of a spring (23) interposed therebetween. The cylinder (11) is on the one hand provided with primary ports (45) for the passage of gas to and from the working chamber (44), which ports (45) at impacting are opened above the hammer piston (15) to ventilate the working chamber (44), and on the other hand with secondary ports (46) for ventilating the volume (47) below the hammer piston (15) during its reciprocation and impacting. The spring (23) is pre-compressed in the machine housing (10) so as to balance the weight of the hammer machine when the latter is kept standing on the tool (20) with the hammer piston (15) resting against the tool (20).

Abstract: An impact element having the effect of elongating the pulse of force in impact tools and devices for chipping, hammering and similar operations, consisting of an element (8) which, for generating the striking motion, is axially moveable as a whole and comprises a driving mass (16) intended to be actuated by a propelling force, and a striking mass (17) located in front thereof relative to the direction of striking, which masses possess a limited freedom of axial movement with respect to each other in that they are coupled together by a stiff spring arrangement, e.g. cup washers (15), extremely hard plastics or gas cushions.

Abstract: A mechanism for maintaining alignment between the gear case or upper portion of a ram type compactor and the spring housing and shoe or lower portion of the compactor which includes a square guide tube and a square hole at the top of the spring housing which reciprocally accepts the guide tube and a segmental wear resistant bearing or bushing forming a lining for the square hole with the bearing being retained in position by the guide tube which extends therethrough and held stationary by the springs in the spring housing. This mechanism enables a person operating a ram type compactor to more effectively handle and maintain proper directional control of the machine.

Abstract: A power operated tool includes a prime mover, an output member and a power transmission mechanism arranged to transmit rotary motion of the prime mover to a reciprocatory output member. The power transmission mechanism includes a first member mounted for reciprocating motion, a link coupled at one end to the first member, and a second member mounted for rotation about an axis transverse to the path of reciprocating motion of the first member. The arrangement is such that rotation of the second member reciprocates the first member and also imparts a cyclic partial rotation to the first member during said reciprocation. The second member has a bore therein spaced from the axis of rotation and inclined there towards. The bore has an axis which intersects the axis of rotation at an angle of about one quarter of the angle through which the first member partially rotates.

Abstract: By providing an inexpensive, easily manufactured coil spring member as a cam surface which is spring biased and is controllably, reciprocatingly axially cycled by a rotating cam follower, an inexpensive, continuous operable, fail-safe, dependable, portable, impactor handpiece is achieved. In the preferred embodiment, the portable, hand-held impacting tool of the present invention also incorporates an inexpensively manufactured and easily installed key member retainingly engaged in an axially elongated slot to prevent unwanted rotation of the anvil member, while assuring continuous, trouble-free reciprocating axial movement thereof.

Abstract: A hammer drill is arranged to rotate and also apply percussive force to a tool receptacle. The percussive force is transmitted from a shaft to a drive piston which, in turn, reciprocates a percussion piston which drives the tool receptacle. The hammer drill includes a housing and a bearing rotatably mounted in the housing. The shaft is rotatably mounted in the bearing and its axis extends perpendicularly of the axis of rotation of the bearing. The bearing supports a contact rim which is in meshed engagement with the shaft. The contact rim is displaceably into frictional contact with a brake member for holding the contact rim against rotation while the bearing rotates carrying with it the shaft. Due to its meshed engagement with the contact rim, the shaft rotates about its own axis causing the drive piston to reciprocate.

Abstract: A portable electric hammer drill incorporates an electric motor 12 disposed close to the handle 13 of the tool and with its axis of rotation at right angles to the axis of rotation of the drill bit holder 10, and a gear 15 on the motor shaft meshes with a first pinion 16 driving the holder in rotation. A second pinion 25 meshes with the first pinion 16 and drives the driving piston 30 of the mechanism for transmitting impacts to the holder. The axes of rotation of the holder 10, the first and second pinions and the gear 15 ;are coplanar, and the first and second pinions are on diametrically opposite sides of the said gear, the first pinion being nearer the handle. This arrangement enables the motor to be placed nearer the handle than if the first pinion were in direct mesh with the said gear, and thus improves the balance of the tool. The arrangement permits the diameters of the first and second pinions to be selected independently of each other.

Abstract: The rotary output of the power source of an impact device is converted to reciprocation of a body, preferably having a resilient coupler, which drives a ram into impacting in an improved rotary-to-reciprocative motion converter including a crankshaft operatively interconnected to reciprocate the body. The converter includes a crankpin bearing, a flat bearing surface secured normal to the reciprocation on a connecting rod or directly on the body, and a constraint spring to hold the flat bearing surface in contact with the bearing during operation. The improved converter provides reciprocation free of angular motion of connecting rods and irregular motion within clearances between moving elements to significantly reduce extraneous harmonic vibrations and energy losses therefrom.

Abstract: A percussive tool has a percussion mechanism driven by a linkage that combines the simplicity of a connecting rod drive with the compactness of more complex drives. A first member, which may be a crank, drives a second member, which may be a cylinder, mounted for sliding and pivotal movement in a guide. A piston is mounted for reciprocating movement in the cylinder. Rotation of the crank reciprocates the piston causing blows to be imparted to a tool piece. The tool piece is rotated as well as being subjected to percussion.

Abstract: A percussion drill comprises an open-ended, hollow cylinder having an air exhaust hole on the side wall thereof, a piston mounted in the rear end portion of the cylinder, and a slide shaft mounted in the front end portion of the cylinder. A drill bit is releasably attached to the forward end of the slide shaft for working with a material. Between the piston and the slide shaft is mounted a striker which forms a forward variable volume air chamber and a rearward variable volume air chamber. The piston is driven by a motor-crankshaft arrangement to reciprocate axially in the cylinder to cause a positive high pressure to develop in the rearward chamber, which pressure provides an impact on the striker whose mechanical energy is transferred to the slide shaft. A return movement of the piston develops a negative pressure in the rearward chamber to pull back the striker to the impact position.

Abstract: In a device which can be used as a hammer drill or a chipping hammer, a percussion mechanism is located within a working cylinder in the housing of the device. A tool can be placed in one end of the working cylinder and the tool can be rotated without any percussive action or it can be given a combined rotative and percussive action. The percussive action is transmitted over a driving mechanism to an actuating piston which reciprocates a percussion piston through an intermediate air cushion. The drive mechanism includes a driving shaft with a disk pivotally connected to the shaft and in engagement with the actuating piston for selectively effecting the percussive action on the tool.

Abstract: A hand-held power tool has a tool holder, a tool axially reciprocable in the tool holder, and a striking mechanism including a drive piston and a striker having a disc-shaped plate with a small axial dimension and a striker shaft having a cross sectional dimension corresponding to that of a tool shaft. The striker shaft transmits impact energy directly to a rear end face of the tool shaft without an intermediate member.

Abstract: An improved air replenishing and idling system for a reciprocating hammer type tool having an outer housing and reciprocal drive mechanism, comprising an elongated barrel mounted within that housing. The barrel includes an axially disposed, air passageway. Slideably positioned within the barrel is a piston member which includes a closed end portion and a hollow, tubular forward portion having first and second air passageways. The piston is reciprocally moved within the barrel by the drive mechanism. Slideably positioned within the hollow tubular portion of the piston is an impact ram. In the operational mode, the ram, tubular portion of the piston member, and barrel cooperate to seal or expose the first and second air passageways and provide a communicative path to the "outside" air through the barrel air passageway whereby the ram is urged axially towards and away from the tool bit through the pressure differentials created.

Abstract: A hand-held power tool has a tool holder for holding a tool, a striking mechanism including a cylindrical sleeve, a drive piston reciprocable in the sleeve, and a striker actuated by the latter, and a drive motor located axially parallel with and laterally adjacent to the cylindrical sleeve. The drive motor transmits the movement to the striking mechanism through a crank drive which is a one-stage crank drive and has a drive train extending transversely to a longitudinal axis of the cylindrical sleeve. The crank drive includes a rotatable shaft, a bevel gear fixedly mounted on one end portion of the drive shaft and meshing with a drive pinion of the motor, and a crank lever mounted on the other end portion of the drive shaft and connected with the drive piston of the striking mechanism. A fan is mounted on the motor shaft and operative for aspirating air, so that air flows through the motor, then flows around the cylindrical sleeve of the striking mechanism and then discharges toward the tool holder.

Abstract: An impact device incorporating an improved air spring coupler in the form of a novel cylinder-piston is disclosed, in which the air spring is linear, i.e., the air spring stiffness is substantially constant over the operating range of the air spring displacement. Selected relations between piston area, ram mass, cylinder volume and equivalent length, crank radius, frequency of impacts and power available in the impact device are disclosed for which the improvement of such linear air spring stiffness is obtained for preferred embodiments.

Abstract: A pneumatic hammer, hammer drill or like percussion tool incorporating a cartridge-type oil tank detachably installed in the main body of the tool. The oil tank is made of transparent or semitransparent material and held from outside by a holding plate formed with at least one slit, permitting the user to check the tank from outside for an oil consumption. The oil tank is supported on a seat plate which is detachably mounted on the tool main body and which, when removed, enables the user to inspect or repair the interior with ease.

Abstract: A hydraulic rotary percussive drill which is adapted to operate as a drill for installing rock bolts in mines is described. The drill is configured so that the shank (which holds the drill steel and bit) forms a right angle with the impact mechanism, thereby reducing the height of the drill and providing longer lengths of drill steel feed in a confined environment. A hydraulic spring force coupler transfers the impact energy from the impact mechanism to the shank, steel and bit and shapes the energy so as to provide force pulses of such length as to couple efficiently the percussive energy to the rock being drilled while reducing the strain in the steel and bit. A rotation mechanism may be mounted in the same leg of the right angle as the shank, steel and bit to rotate the steel and bit independently from the percussive action.

Abstract: The housing for electric tools comprises a one-piece plastic construction and includes a handle part and a hollow housing part having a metal jacket therein which defines various cavities and bearing bushes and bores for the elements of a drive motor and an eccentric drive for a hammer drill.

Abstract: A hammer drill has a motor-actuated drive piston and a free percussion body accommodated in a common, stationary cylinder. The percussion body is caused to move back and forth by the drive piston with air as the coupling and buffer medium. The hammer drill further has a tool holder driven by a hollow drive shaft which encloses the stationary cylinder and is driven by a motor which also actuates the drive piston.

Abstract: An impact device, incorporating power drive means having a resilient drive element for generating successive ram impacts against a tool by reaction of the resilient drive element against the device frame, incorporates resilient bias means, interposed between the frame and the tool, to continuously transmit bias force from frame to tool acting to hold the tool firmly against a workpiece during operation, while resiliently suspending the frame for free dynamic motion clear of motion limiting stops, thereby eliminating spurious tool and frame motions and directing the impact energy of the ram to more efficiently and effectively accomplish impact work.

Abstract: An impact device incorporating an improved air spring coupler in the form of a novel cylinder-piston is disclosed, in which the air spring is linear, i.e., the air spring stiffness is substantially constant over the operating range of the air spring displacement. Selected relations between piston area, ram mass, cylinder volume and equivalent length, crank radius, frequency of impacts and power available in the impact device are disclosed for which the improvement of such linear air spring stiffness is obtained form preferred embodiments.

Abstract: Rotary-powered exciter-reciprocative means are disclosed by which improvements in efficiency and effectiveness of impact devices, effected by important reductions of wasteful extraneous harmonic vibrations through the use of long double connecting rods, are obtainable in selected embodiments incorporating gearing, by which a smaller lighter weight rotary motor of different rotational frequency from that of the impacting can be utilized.

Abstract: In the manually guided tamping machine comprising a vertically long casing, a motor mounted thereon, crank means driven thereby, a cylinder snugly mounted to be vertically movable in said casing, a percussion piston in said cylinder, and a pair of coil springs disposed above and below said piston in said cylinder so as to generate vibrating reciprocation to be transmitted to the tamper foot, the invention is characterized by disposing said crank means not at the casing top as usual wherein a relatively long and thin connecting rod or ramrod must pass through the coil spring but vertically amid and in the cylinder, and providing a pair of pistons instead of one in the prior art so as to be subjected to alternate upward and downward movement by means of a pair of connecting rods pivotally linked to said crank means. A shaft for driving said crank means is transversely extended through a vertical slot formed in the cylinder wall and bearings mounted on the casing.

Abstract: A power driven crankshaft is mounted on a frame and is connected by a pair of connecting rods to a coupler body, having guide means thereon to limit movement of the body to straight line reciprocation. Selected positioning and arrangement of crankshaft, bearings, connecting rods, journals, wrist pins, power drive means, reciprocating body guide means and selected crankarm result in high impact force being delivered to an impact tool with significantly reduced energy loss caused by oscillatory structural deflections spurious vibrations, and rotations. An improved coupler incorporates an air spring with selected central vent means resulting in nearly constant spring stiffness.

Abstract: A hammer mechanism is disclosed, which incorporates a hammer piston driven by a driving piston via a pressure-gas cushion in a working chamber. The hammer piston controls the transference of flushing gas from the working chamber to the tool during normal operation and has an extreme position in which the hammer piston does not interfere with the transference of flushing gas.